The present invention is intended to be used with instrumentation which is disclosed in U.S. Pat. No. 4,863,430 entitled "INTRODUCTION SET WITH FLEXIBLE TROCAR WITH CURVED CANNULA" issued on Sep. 5, 1989 and U.S. Pat. No. 4,678,459 entitled "IRRIGATING, CUTTING AND ASPIRATING SYSTEM FOR PERCUTANEOUS SURGERY" issued on Jul. 7, 1987, both patents being incorporated herein by reference. Essentially, the introduction set includes a trocar which is initially introduced and used to guide a cannula to a position adjacent a surgical site. Once this is accomplished, the system for percutaneous surgery can be introduced through the cannula and the surgical procedure performed.
Often times before a surgical procedure is performed, certain diagnostic procedures are used to evaluate the surgical site to determine the advisability of the surgical procedure. For example, there is currently available on the market a surgical needle with a removable hub, which surgical needle can be used for directing a diagnostic fluid to a potential surgical site. If subsequent radiological images indicate that surgery is appropriate, the hub of the needle can be removed so that the needle can act as a trocar in order to guide other instrumentation to the surgical site. In this prior device, the hub is comprised of at least two portions which can be screwed together in order to compress an o-ring which holds the hub fixed relative to the needle. Once the two components of the hub are unscrewed, the O-ring is released, allowing the pieces to be slid off of the needle so that the needle can then be used as a trocar. With such an arrangement, it is possible that the hub could be reassembled onto the needle and the needle reused. Such reuse is often times not recommended or advisable and poses a disadvantage to this apparatus.